Setup Reseller Account

I am sure this has been answered before - but either that last statement is infact incorrect or my search terms are rubbish either way.... a response by linking to a thread or a posted reply will be appreciated

I have setup a reseller account

the main acccount

reseller.com has been give 10GB Space and 10GB Bandwith.

I have then enabled reseller.com to be a reseller

in the reseller options I have not limited his account. e.g can create unlimited accounts
Now my thinking of this is that the reseller is able to offer unlimited accounts, and when his 10GB runs out he will ask to buy more from me....

But re-reading the options I am now confused if this is the case. If the main reseller.com account limits the rest all well and good

But if not then.......

1.can the reseller "sell" and therefore setup accounts with more space then he has actually bought e.g give out 15GB worth of bandwith

2. can the reseller offer unlimited accounts

3. When setting up the account, what do you give the main domain as the intial offfering.... (if the above is all false)